Atmospheric aerosol particulate matter less than 2.5 microns in size (PM2.5) and ozone are major causes of degraded air quality, both adversely affecting human health and climate. The sources of PM2.5 and ozone in urban areas have complex relationships that may lead to co- benefits in policy attempts to regulate one or the other. The goal of the project is to conduct comprehensive, online and near real-time molecular-level measurements of gas and particle composition as part of the NOAA AEROMMA field campaign in two locations of the New York City metro region. The molecular-level information on an hourly basis of both gas and aerosol composition enables uniquely quantitative and detailed source apportionment of the organic aerosol fraction. This provides insights into not only important primary emission sources but also into relevant chemical processes governing the sensitivity and evolution of organic aerosol to changing climate variables, such as temperature, and anthropogenic emissions such as VOC and NOx. The project provides a unique set of observations and analyses that address fundamental questions about the impact of anthropogenic and biogenic emissions together with changing temperatures on urban PM sources and abundance.